An upgrade from the MahaDevi
robot of years past, the GanaPatiBot
has multiple drums, each with its
own solenoid systems for striking the
drum which enables a variety of
textures, as well as increasing the
speed of a drum rool to well beyond
any humanly achievable speed, Kapur
commented.

One year, the roboticists put a
propeller Leslie system at the rear of
the GanaPatiBot with two speakers
placed at either end of a motorized,
spinning bar which played sounds
and drones from an iPod Mini
attached near the middle of the bar.
Because the speakers flew off
making the setup dangerous, the
team no longer uses this
configuration.

The students and instructors
develop a new GanaPatiBot each
year using their own style, aesthetics,
and system of building. “We upgrade
everything year after year, including
the electronics,” says Kapur.

Rear view of the GanaPatiBot.

The MahaDeviBot

The MahaDeviBot beats
out most small drum kits
for greatest number of
drumming surfaces.

This was the first robot
musician/instrument that Kapur built
for his PhD project while on
Vancouver Island. “It was the proof
of concept that I could do all this
work. I built it out of 80/20 slotted
aluminum,” says Kapur.

The MahaDevi uses a circuit
board — the circuit was designed in
CAD and manufactured especially for
the class — to actuate each arm and
corresponding solenoid. “I write the
code for the students so they can begin to work with this
robot,” Kapur explains.

Kapur turned the robot into a MIDI device. “It takes a
lot of programming, which in itself is an entire stage of the
design and build process,” explains Kapur. Still, the students
are doing most of the actual performances on the robot, in
real time. The robots can also be pre-programmed to
perform pieces autonomously.

The robot’s brains consist of Atmel chips and circuits,
Arduino’s open electronics prototyping, and a ChucK server
to run the server that controls it all. The data transfers via
MIDI over USB technology.

Designed by Kapur, the robot is a robotic extension of

Saving on Solenoids

The CalArts class that builds the mechanized
musical wonders saves big bucks on solenoids by
searching for older models in the discarded
typewriters, printers, and other devices that line the
local junkyards. “It is a savings and it is cool because we
are recycling the solenoids,” says Ajay Kapur, Orchestra
Leader and Instructor, CalArts.